linux-kernel - Re: [PATCH] media: davinci: vpif_capture: fix potential double free

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Message-ID: <CA+V-a8uNfscxiM1fMjfdvZstZkkzxW41p40jpBXT3NeyiS9-Qw@mail.gmail.com>
Date:   Fri, 24 Jul 2020 15:16:57 +0100
From:   "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To:     Evgeny Novikov <novikov@...ras.ru>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-media <linux-media@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>, ldv-project@...uxtesting.org
Subject: Re: [PATCH] media: davinci: vpif_capture: fix potential double free

Hi Evgeny,

Thank you for the patch.

On Thu, Jul 23, 2020 at 6:04 PM Evgeny Novikov <novikov@...ras.ru> wrote:
>
> In case of errors vpif_probe_complete() releases memory for vpif_obj.sd
> and unregisters the V4L2 device. But then this is done again by
> vpif_probe() itself. The patch removes the cleaning from
> vpif_probe_complete().
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Evgeny Novikov <novikov@...ras.ru>
> ---
>  drivers/media/platform/davinci/vpif_capture.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/drivers/media/platform/davinci/vpif_capture.c b/drivers/media/platform/davinci/vpif_capture.c
> index d9ec439faefa..72a0e94e2e21 100644
> --- a/drivers/media/platform/davinci/vpif_capture.c
> +++ b/drivers/media/platform/davinci/vpif_capture.c
> @@ -1482,8 +1482,6 @@ static int vpif_probe_complete(void)
>                 /* Unregister video device */
>                 video_unregister_device(&ch->video_dev);
>         }
> -       kfree(vpif_obj.sd);
> -       v4l2_device_unregister(&vpif_obj.v4l2_dev);
>
vpif_probe_complete() is a async callback and probe() should have
already completed by then.

Cheers,
--Prabhakar

>         return err;
>  }
> --
> 2.16.4
>